Los Angeles — Jay Leno may not be a "whiner," as he put it in response to the criticism his new 10 p.m. prime time show has faced. But this week, he certainly had plenty to worry about as his freshman variety show on NBC, airing five nights a week against mostly scripted dramas on the other networks, fell behind a re-run of CSI: Miami.

After debuting to impressive numbers on Sept. 14 – some 18 million viewers – "The Jay Leno Show" over the past two weeks has settled into nearly identical ratings as its late-night predecessor, roughly five million viewers nightly. NBC had maintained that it would be satisfied with lower ratings as long as the show earned a net profit (a talk show costs a fraction of a scripted show, which can top $4 million per episode). But it had asserted that the show would shine when the other channels were airing re-runs.

Even worse, in what has already been dubbed "the Leno effect" – audiences lost by 10 p.m. often don't return for later programs – ratings for NBC's two, later talk shows with Conan O'Brien and Jimmy Fallon are also down and viewership for the 11 p.m. news programs at NBC affiliates from Miami to New York is off by nearly a third.

In short, say media analysts and industry insiders, "The Jay Leno Show" is not delivering for the network's prime time schedule, its late night line-up, or the overall broadcast network industry.

In part, the show has been a victim of its own hype. It debuted amid myriad promises of new faces and formats, including showcases for new young comics and a more urgent, topical tone. Washington-based comedian D. L. Hughley was going to bring national politics to the studio and evening news anchor Brian Williams was going to deliver newsy bits.

Instead, points out James Hibberd of The Hollywood Reporter, the show is not much different in both style and tone from what audiences saw night after night on the old "Tonight Show" for 17 years – a lightweight, celebrity-obsessed hour. That's partly why the show has become "everybody's favorite pinata" in a time of uncertainty about where the broadcast model is headed, he says. As Leno's show muddles along behind the other networks, "it's seen as somehow un-American to aim for third place," he adds with a laugh.

Clearly, the move away from serious, scripted material was a mistake, says former network executive Doug Spero, who is now a professor of mass communication at Meredith College in Raleigh, N.C. "The light and fluffy type of show doesn't have enough depth to sustain a sizeable audience."

It's ironic that "in the long run high-quality drama is actually more valuable," says Ms. Blakley, because it can be re-packaged and re-sold for years beyond its original use – which cannot be done with a talk show.

Beyond that, she adds, if the broadcast model begins to lose viability and audiences find fewer shows that can draw large numbers, the cultural impact will be significant.

"We have fewer and fewer sources of shared, cultural touchpoints," says Blakley, "and the broadcast networks are one of the few places left for that. They provide avenues for us to reach across social, economic and class barriers to communicate with each other. This would be unfortunate to lose."

Executives at both NBC and "The Jay Leno Show" did not respond to requests for comment.